The present invention relates to a display arrangement for a video system. In particular, the invention provides for a holographic video screen, which appears black, gray or colored in ambient light, as a display system for information systems.
Various types of display apparatus and display video screens (displays) are known. For example, it is known to use cathode ray tubes, which require a relatively large amount of energy and space. Furthermore, LCD-displays are also known. Other display possibilities are fixedly mounted and are not easily changed. In addition, display systems are known which use a (preferably white) projection surface to display an image for reasons of good backscatter characteristics. Therefore, to achieve a high contrast, it is necessary to provide an operational environment which is as dark as possible, in order to avoid the backscattering of ambient light and to provide a brilliant display of the image.
German Patent applications 197 00 162.9 and 197 03 592.2, which are not prior publications, disclose a holographic video screen for a laser front projection and a laser rear projection. In normal ambient light, the video screen is black. However, for certain wavelengths of light, this video screen may be constructed such that the light is transmitted and transmitted back within a certain solid angle. In the embodiments disclosed in these two patent applications, the video screen need not have a planar construction; rather, it may have an almost arbitrary surface contour. This arrangement has the advantage that the virtual display of the image can be applied at almost any arbitrary distance.
An object of the present invention is to provide a display arrangement for an information processing system which is compact, energy efficient and easily changed.
Another object of the invention is to provide a display arrangement which can be arranged at a virtually arbitrary spacial position relative to an image provided thereby.
These and other objects and advantages are achieved by the display arrangement according to the invention in which a holographic image is used to provide an output display in an information processing system. The display according to the invention, comprising a holographic device, may appear as black, gray or colored in ambient light; if the video screen appears in color, it is advantageous that it appear in a dark color, to achieve good contrast.